When enable this it will allow symlinks to watch recursively out of the pointed directory. follorSymlinks must be enabled to this work. For example, added symlink to /home/folder, and the symlink points to /, this by default is not allowed, it's only allowed to symlink anything from /home/ and deeper. This is to avoid great levels of recursion. Enabling this could lead in infinite recursion, and crash the watcher ( it will try not to avoid this ). Buy enabling out of scope links, it will allow this behavior. allowOutOfScopeLinks are disabled by default.